See How Our Pitcher Ratings Have Changed Since Opening Day

One of the cool features in our MLB predictions model at FiveThirtyEight is its ability to adjust a team’s odds of winning any given game based on the strength of its starting pitcher. We do this by maintaining a constantly updating rating of every starter in baseball, which refreshes after every start based on our version of game score — a metric that grades pitching performances using stats such as strikeouts, walks, home runs and so forth.15
And who do our ratings say are the best starters in baseball? Here’s how the Top 20 looked on opening day and how it’s changed since:

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One of the cool features in our MLB predictions model at FiveThirtyEight is its ability to adjust a team’s odds of winning any given game based on the strength of its starting pitcher. We do this by maintaining a constantly updating rating of every starter in baseball, which refreshes after every start based on our […]

A number of the top aces at the beginning of the season have started the season on the wrong foot. The New York Mets’ Jacob deGrom, Boston’s Chris Sale, Cleveland’s Corey Kluber and Philadelphia’s Aaron Nola have all seen the biggest drop-offs from the original Top 20. Because the ratings roll over from last season, that group hasn’t dropped too far, but they have lost some of their status since the season began. But a handful of others have either pitched their way up the list with good starts (Justin Verlander, Trevor Bauer, German Marquez, Mike Clevinger) or onto it from the outside since the beginning of the year (Cincinnati’s Luis Castillo, Texas’s Mike Minor).
These changes matter for our overall season predictions. Game score ratings aren’t just fun — they can have quite an effect on a team’s chance of winning: The Tampa Bay Rays’ chance of beating an average team (on a neutral field) with ace Blake Snell, for instance, is 61 percent; with a league-average starter, that number drops to 53 percent. To help you follow the state of each rotation, we recently added a new feature to our predictions interactive tracking these ratings for every team’s pitching staff (sorted by division). Now we can visualize just how much better Verlander and his fellow Astros are than the rest of the AL West…

… as well as the sad state of the Orioles’ rotation (whose only above-average starter is journeyman Nate Karns):

You can also see how a rotation’s starters stack up against its division foes on our team pages. Here, for example, are the Cleveland Indians, who might have the best rotation in baseball right now:

As always, these ratings update after every game to help you stay on top of the latest predictions and World Series odds.
Check out our latest MLB predictions.